I. Field of the Invention
The present invention relates to a liquid measuring dispenser for dispensing a pre-measured amount of liquid.
II. Description of the Related Art
There are many instances in which it is desired to dispense an accurately measured amount of liquid from a bottle. One area where this need is prevalent is in the medical field. A measuring dispenser is commonly used to measure quantities of liquid poured from a medication bottle. The stand alone measuring dispenser is not a completely satisfactory device for measuring liquids. Being a separate unit, the dispenser can be misplaced. Also, the dispenser is prone to overfilling, underfilling, and spills. Further, the separate dispenser requires the medicine bottle to be opened which creates a potential for contamination of the medicine. As a result of these drawbacks, it has been a common goal in the art to invent a self-contained metering dispenser which can be integrated with the medicine bottle.
There are several types of integral, pre-measured liquid dispensers existing in the prior art. Among the most common types of dispensers are those that have separate storage and dispensing chambers. In order for these dispensers to accomplish their goal of self contained metering of liquid, the chambers must communicate with each other. Liquid dispensers are commonly constructed of either rigid or deformable walls. Usually the deformable walled dispensers have a conduit tube through which the liquid, which is pressurized by the deformation of the walls of the dispenser, flows into the dispensing chamber. An alternative to the pressurized flow of a deformable dispenser is the inversion type dispenser which relies on the force of gravity to transport the liquid from the storage chamber to the dispensing chamber. The present invention concerns the inversion type dispensers and may be constructed with rigid or deformable walls.
U.S. Pat. No. 3,141,579 discloses a liquid measuring dispenser that utilizes separate storage and dispensing chambers and may be constructed of rigid or deformable walls. In the embodiment with deformable walls, the liquid measuring dispenser has a storage chamber and a metering chamber which are divided by a necked down portion of the dispenser. A spring biased plunger fills the opening in the necked down portion between the two chambers and prevents liquid from entering the metering chamber from the storage chamber. When the sides of the dispenser are squeezed, the liquid in the storage chamber forces the plunger to retract which allows the liquid to pass into the metering chamber. Once the metering chamber is filled, the plunger shuts off the flow of liquid from the storage chamber. The resulting measured liquid can be held in the metering chamber or dispensed through a spout at the top of the dispenser.
The same patent also discloses a rigid walled device which operates under similar principles. The device has a double acting plunger which is biased by means of a spring. The outlet of the metering chamber is closed by one end of the plunger, and the other end of the plunger closes off the orifice between the storage chamber and the metering chamber. In its biased position, the outlet of the measuring chamber is closed by the end of the plunger being seated in the outlet orifice, and the orifice between the storage chamber and the measuring chamber is opened by the other end of the plunger being retracted. Thus, in the biased position, inversion of the dispenser allows liquid to pass into the measuring compartment. When an actuating button is depressed with the dispenser in the inverted position, the double acting plunger will be moved along the inside of the dispenser such that the first plunger will open the outlet of the measuring compartment and the second plunger will close off the orifice between the storage chamber and the metering chamber. In order to allow for smooth flow of the liquid from the exit portion of the dispenser, the exit spout is equipped with an air valve.
While the prior art device accomplishes the goal of self contained metering of liquids, the present invention accomplishes the goal with a device that is easier to use, easier to manufacture, and more reliable due to its simpler construction.